{"api_version":"1","generated_at":"2026-11-07T01:13:12+00:00","cve":"CVE-2026-19574","urls":{"html":"https://cve.report/CVE-2026-19574","api":"https://cve.report/api/cve/CVE-2026-19574.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-19574","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-19574"},"summary":{"title":"ARM64 MMU can assign an in-use ASID to a new memory domain, breaking user-mode memory isolation","description":"The ARM64 MMU back-end allocated address space identifiers (ASIDs) for memory domains with a bare round-robin counter in arch_mem_domain_init() (arch/arm64/core/mmu.c). VM_ASID_BITS is 8, so only 255 ASIDs exist; once the counter wrapped, arch_mem_domain_init() could hand an ASID to a new domain while a still-live domain held the same one. Domain-private mappings are installed non-global (MT_NG), so the ASID is the only tag separating one domain's cached translations from another's in the TLB.\n\nThe context-switch path in z_arm64_swap_ptables() only flushes the TLB when the outgoing and incoming domains carry the same ASID, which does not cover a duplicate reached through a third domain: for domains A and C sharing an ASID and an unrelated domain B, the schedule A -> B -> C never takes the flush branch, so the ASID-tagged entries A populated remain resident while C runs. Under SMP two live domains sharing an ASID can additionally be resident on two CPUs at once, which the architecture does not allow for distinct translation-table sets.\n\nTriggering the wrap requires a CONFIG_USERSPACE application on ARM64 that creates more than 255 memory domains over its lifetime; k_mem_domain_init() and k_mem_domain_deinit() are supervisor-only APIs and are not exposed as syscalls, so an unprivileged thread cannot drive the counter directly. Once two live domains alias, however, a user-mode thread in one domain can read and write memory belonging to the other domain's partitions and thread stacks with that domain's permissions, defeating the memory-domain isolation boundary.\n\nThe fix scans the live domain_list before assigning an ASID, advances the round-robin counter past ASIDs already in use, and returns -ENOMEM when all are taken, so domain creation fails closed instead of silently aliasing.","state":"PUBLISHED","assigner":"zephyr","published_at":"2026-10-09 08:16:54","updated_at":"2026-11-04 05:18:48"},"problem_types":["CWE-284","CWE-284 auth"],"metrics":[{"version":"3.1","source":"vulnerabilities@zephyrproject.org","type":"Secondary","score":"7","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"7","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/805054b8ed89dd5441fbca36b3cd3be7e4fb4100","name":"https://github.com/zephyrproject-rtos/zephyr/commit/805054b8ed89dd5441fbca36b3cd3be7e4fb4100","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-923h-8c2j-pcm5","name":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-923h-8c2j-pcm5","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-19574","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19574","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"zephyrproject","product":"zephyr","version":"affected 3.3.0 4.3.2 semver","platforms":[]},{"source":"CNA","vendor":"zephyrproject","product":"zephyr","version":"affected 4.4.0 4.5.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"19574","cve":"CVE-2026-19574","epss":"0.000970000","percentile":"0.007120000","score_date":"2026-11-04","updated_at":"2026-11-05 00:04:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-19574","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","timestamp":"2026-10-09T17:56:13.062546Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-10-09T17:56:48.909Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","defaultStatus":"unaffected","packageName":"zephyr","product":"zephyr","programFiles":["arch/arm64/core/mmu.c"],"programRoutines":[{"name":"arch_mem_domain_init"},{"name":"k_mem_domain_init"}],"vendor":"zephyrproject","versions":[{"lessThan":"4.3.2","status":"affected","version":"3.3.0","versionType":"semver"},{"lessThan":"4.5.0","status":"affected","version":"4.4.0","versionType":"semver"}]}],"descriptions":[{"lang":"en","value":"The ARM64 MMU back-end allocated address space identifiers (ASIDs) for memory domains with a bare round-robin counter in arch_mem_domain_init() (arch/arm64/core/mmu.c). VM_ASID_BITS is 8, so only 255 ASIDs exist; once the counter wrapped, arch_mem_domain_init() could hand an ASID to a new domain while a still-live domain held the same one. Domain-private mappings are installed non-global (MT_NG), so the ASID is the only tag separating one domain's cached translations from another's in the TLB.\n\nThe context-switch path in z_arm64_swap_ptables() only flushes the TLB when the outgoing and incoming domains carry the same ASID, which does not cover a duplicate reached through a third domain: for domains A and C sharing an ASID and an unrelated domain B, the schedule A -> B -> C never takes the flush branch, so the ASID-tagged entries A populated remain resident while C runs. Under SMP two live domains sharing an ASID can additionally be resident on two CPUs at once, which the architecture does not allow for distinct translation-table sets.\n\nTriggering the wrap requires a CONFIG_USERSPACE application on ARM64 that creates more than 255 memory domains over its lifetime; k_mem_domain_init() and k_mem_domain_deinit() are supervisor-only APIs and are not exposed as syscalls, so an unprivileged thread cannot drive the counter directly. Once two live domains alias, however, a user-mode thread in one domain can read and write memory belonging to the other domain's partitions and thread stacks with that domain's permissions, defeating the memory-domain isolation boundary.\n\nThe fix scans the live domain_list before assigning an ASID, advances the round-robin counter past ASIDs already in use, and returns -ENOMEM when all are taken, so domain creation fails closed instead of silently aliasing."}],"metrics":[{"cvssV3_1":{"baseScore":7,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-284","description":"auth","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-04T05:00:43.926Z","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","shortName":"zephyr"},"references":[{"name":"Fix commit","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/805054b8ed89dd5441fbca36b3cd3be7e4fb4100"},{"name":"GHSA-923h-8c2j-pcm5","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-923h-8c2j-pcm5"}],"title":"ARM64 MMU can assign an in-use ASID to a new memory domain, breaking user-mode memory isolation","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","assignerShortName":"zephyr","cveId":"CVE-2026-19574","datePublished":"2026-10-09T07:16:43.058Z","dateReserved":"2026-08-11T19:47:42.367Z","dateUpdated":"2026-11-04T05:00:43.926Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-09 08:16:54","lastModifiedDate":"2026-11-04 05:18:48","problem_types":["CWE-284","CWE-284 auth"],"metrics":{"cvssMetricV31":[{"source":"vulnerabilities@zephyrproject.org","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-09T17:56:13.062546Z","id":"CVE-2026-19574","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"19574","Ordinal":"1","Title":"ARM64 MMU can assign an in-use ASID to a new memory domain, brea","CVE":"CVE-2026-19574","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"19574","Ordinal":"1","NoteData":"The ARM64 MMU back-end allocated address space identifiers (ASIDs) for memory domains with a bare round-robin counter in arch_mem_domain_init() (arch/arm64/core/mmu.c). VM_ASID_BITS is 8, so only 255 ASIDs exist; once the counter wrapped, arch_mem_domain_init() could hand an ASID to a new domain while a still-live domain held the same one. Domain-private mappings are installed non-global (MT_NG), so the ASID is the only tag separating one domain's cached translations from another's in the TLB.\n\nThe context-switch path in z_arm64_swap_ptables() only flushes the TLB when the outgoing and incoming domains carry the same ASID, which does not cover a duplicate reached through a third domain: for domains A and C sharing an ASID and an unrelated domain B, the schedule A -> B -> C never takes the flush branch, so the ASID-tagged entries A populated remain resident while C runs. Under SMP two live domains sharing an ASID can additionally be resident on two CPUs at once, which the architecture does not allow for distinct translation-table sets.\n\nTriggering the wrap requires a CONFIG_USERSPACE application on ARM64 that creates more than 255 memory domains over its lifetime; k_mem_domain_init() and k_mem_domain_deinit() are supervisor-only APIs and are not exposed as syscalls, so an unprivileged thread cannot drive the counter directly. Once two live domains alias, however, a user-mode thread in one domain can read and write memory belonging to the other domain's partitions and thread stacks with that domain's permissions, defeating the memory-domain isolation boundary.\n\nThe fix scans the live domain_list before assigning an ASID, advances the round-robin counter past ASIDs already in use, and returns -ENOMEM when all are taken, so domain creation fails closed instead of silently aliasing.","Type":"Description","Title":"ARM64 MMU can assign an in-use ASID to a new memory domain, brea"}]}}}